Sample: get consumed storage of a vm, excluding the snap shot drives?

Reference: https://github.com/vmware/pyvmomi/issues/111

I've notice when summarizing the consumed storage for billing purposes that you get variable data due to snapshots. The size of consumed grows based on if there is a snap shot or not. is there a way to account for this and get actual consumed storage of a vm excluding the snapshots?

currently im using the following ways to get consumed: round(Decimal(vm['summary.storage.committed'] + vm['summary.storage.uncommitted']) / Decimal(1.0 * 2**30), 5)

Create a full sample that demonstrates various ways to look at the consumed datastore storage of a virtual machine.